Forty-three patients with spontaneous bacterial peritonitis (SBP) between 1973 and 1978 were identified. Criteria for SBP included a positive ascites culture and polymorphonuclear cell concentration greater than 250 cells per mm3. Chronic liver disease was documented by vayces in 91%, severe histologic fibrosis or cirrhosis in 94%, splenomegaly in 91%, and past hospitalization for liver disease in 57% of the patients. SBP was detected within 7 days of admission in 17 patients (40%) and within 35 days in 38 patients. Single organisms were isolated from 38 patients and multiple organisms from 5 patients. Twenty-six of 43 patients survived the episode of SBP, but only 13 survived the hospitalization. Analysis of the survival curve from the onset of SBP revealed a rapid death rate and a slow death rate set of patients. Rapid death (5 7 days from SBP onset) correlated with a lack of prior hospitalization for liver disease (p < 0.001), hepatomegaly (p < 0.001), increased serum bilirubin (p < 0.005), serum creatinine (p < 0.05), and peripheral white blood cell concentrations (p < 0.05). Survival during hospitalization was associated with prior hospitalization with liver disease (p < 0.001) and chills during the episode of SBP (p < 0.001). The 43 patients were divided into Group 1 patients on the basis of a serum bilirubin > 8 mg% and/or serum creatinine > 2.1 mg%; Group 2 patients had lower values. Survival was greater in Group 2 patients with advanced, relatively quiescent liver disease compared to Group 1 patients for both the episode of SBP (91 vs. 29%; p < 0.001) and for hospitalization (50 vs. 9%; p < 0.05). Death in Group 2 patients was related to inadequate antibiotic therapy (p < 0.05), nonhepatic factors, and new onset of renal failure. Although SBP in the setting of severe acute liver injury has a dismal prognosis, SBP with minimal acute liver injury has a relatively good prognosis for hospital survival even with advanced chronic liver disease. Long-term survival is also possible since 4 of 9 patients with prolonged follow-up have survived 3 years.